Boiler blow-off and circulating device



Nov. 8, 1927. 1,648,028

' G. PURvls BOILER BLOW-OFF AND CIRGULATING DEVICKFJ Filed Nov, `29, 1918 2. Sheets-Sheet l 7 ZVJ Nov. 8, 1927.

G. PURVIS BOILER BLOW-OFF" AND CIRCULATING DEVICE FiledQNov. 29. 1918 2 Sheets-Sheet 2 @VMM eco Patented Nov. 8, 1927a UNITEDN srN frs attains erinnernrun-vis,v or DETROIT, intentarn.

:BOILER Brewers ann ornonizarine nevica.

applicati@ ined november 2e, 191s. serial no. 254,483,

This invention relates to a blow-oft' and circulating device for steam boilers and more particularly to an arrangement of a selective valve thereof whereby the circulation part of the system may be cut out of useas desired, while the valve itself is bal-` ancedfand is readily accessible and manipulatable from the ,exterior of the boiler. n f The invention consists in the mattershereinafter set forth7 and more particularly pointed out in the appendedclaims.v

In the drawings,

lll

Figure 1 is a viewin longitudinal section of a steam boiler of conventional typeprovided with a device that embodies features of the invention; i Fig. 2 is a view ofthe rear head of the boiler;

Fig. 3 is a view in detail, partly in eleva- 2" tion land partly in longitudinal section of a selective valve f f Fig. 4: is a view in cross section taken on or about line IWL-IV of Fig. 3

Fig, 5 is-a view in detail of an indicating they flange being centered on an outlet nipple 8 of the casing which is preferably concentric therewith. The fitting leads to va blowoif valve 9 of suitable type. .A rotatable stern 10 extends through the fitting and the bore of the nipple 8 into ynon-rotatable engagement with a valve closure 11, the inner end portion 12 of the stern being stepped in V an inner head 13 of the casing which is secured thereto by suitable studs 14 or the like. Preferably a squared or splined pori tion 15 of the stem engages into an opening in the end wall of the closure. The latter has a conoidal side wall 16 terminating in an outlet nipple 17 that is journaled in the counterbored opening of the outlet boss 8. A port 18 formed in .theend wall 30 of the closure may be brought into register with an inlet opening of the wall 13 by rotation of the cloaure.. This inlet opening is connected by a conductor 19 with' a suitable collecting nozzle 20 which is placed in the boiler where the sediment and mud usually collect., the nozzle'being so disposed as to readily draw in the sediment under the ejector actionFof the device. @if course, more than oneffcollector nozzle may be placed in the boiler-and there may be as many openings in the yend wall of the valve Casin as there are nozzles and connecting pipes witheach one ofwhich theport'lS may be brought into register, A

water level of the boiler, isconnectedfby a pipe 22 with an opening in the valve Vcasing surface blow pan 21, which is at the normal n through the head walll, this opening being likewise arranged to be broughtinto regis ter with the port 18. A circulating pipe 23, from the lower portion of theboilernshell leads to a lateral boss 24 in the valvecasing into the bore of which it opens. c As shown in'Figs. 2 and 4, casing 1 is providedwith an upwardly-extending boss 31, thisqboss rhaving an opening leading to theinterior of the casing exteriorlyto the valveclosure, the upper end of the boss* being below the normal waterlevel of the boiler as indicated in Fig. 2, the boss being` belowwthe level of blow-pan 21. r This places the space exterior of the valve closure 1n communication-'with the bottomiof the boiler through pipe 23 and with the `upper water level 'portion through the boss 31. Consequently it produces a practically balanced action yon the valve closure. Whenever it is desired to out vthe circulating pipe out of action7 a` lateral lug 25 on the closure is arranged to befbrought into register with the openingthrough the boss 24, thereby sealing the latter. A suitable handle 26 manipulates `the stem; 10` `and an index pointer 27 sweeping ak dial plate28 shows the position of the valve "so lthat the same may be readily manipulated from the boiler exterior. y

As will be understood, the difference in temperature between the water content'at the inlet of pipe 23 and of the outlet of pipe 31 is necessarily of material amount, since the portion of the water below the grate line is substantially static while that of the upper level is at the point of evaporation. In addition, however, pipe 23 is carried across the top of the fire box, thus bringing it into a zone where the walls of the boX provide heating action `of the water content, thus materially increasing the temperature of the content of pipe 23 this point Hence, the variation in temperaturebetween the inlet and outlet provided by this line of communication between the bottom ot the boiler and the water level, acts to set up a circulation therein by reason ot the tendency of the warmer portion to rise within the line, discharging through boss 3l-this being aided by the location ot the horizontal portion of pipe 23T-with the result that the inlet end ot' pipe 23 is constantly receiving a new supply from the static portion of the boiler content and disturbing the latter to this extent. Y

This action takes place whenever pipe Q3 is not closed by lug 25. Obviously, this circulation actiony willtend to circulate sediment as well. Under ordinary ruiming conditions the amount of sediment within the boiler which would be affected by this circulation is of such small amount as to be negligible, but where the vessel is in harbor where the water supply carries a much greater percentage, the feed ot this water into the boiler introduces a much larger percentage, making it inadvisable to continue this circulation action during this period, the static condition being permitted to remain and permitting the sediment to settle where itrcan be blown out when the next blow-oli operation takes place. In other words, it is desirable to prevent this circulation action during the period when the vessel is entering or leaving port, during which thebacking and forward movements are had with the bottom of the vessel close to the bottom of the'channel.

As will be seen the arrangement ot the circulation means is suchas to produce somewhat of a thermo-siphonic action through the fact that the content of thecirculating passage varies practically trom water' to steam, the entrance to the passage being below the line of evaporation and the outlet at ysubstantially the point of lgreatest evaporation, with the lire box wall itself aiding in enhancing the circulating action.

It will be understood, of course, that the length of boss 3l will depend on the position of the casing in the boiler relative to the normal water level, and where such position brings the casing closer to the level than that shown, the boss may be omitted and the perforation through the casing wall be utilized, it being preferred that the outlet for the circulation be slightly below the normal water level as shown.

Obviously, changes in the details ot con struction may be made without departing from the spirit of my invention and I do not care to'limit my self to any particular form or arrangement of parts.

lVhat I claim is l. The combination with a boiler, ol valve means mounted thereon and having a chamber therein, a blow off pipe and a discharge pipe communicating with each other through the valve means and leading therefrom respectively to the bottom ot the boiler and to a point exterior of the boiler, means for establishing circulation within the boiler and comprising conduits leading Vfrom said chamber substantially to the bottom and to the normal water level line of the boiler respectively, said valve means comprising a movable element having portions adapted respectively to close said blow oil' pipe and to interrupt circulation through said conduits.

2. The combination with a boiler o't' a valve casing mounted thereon and having a chamber therein, a valvein said casing, draw oiic pipes leading from said casing and respectively having ends opening substantially .at the bottom and the normal water level line ot' the boiler, a discharge pipe leading from said casing to a point outside the boiler. means for promoting circulation within said boiler and comprisingconduits coi'mnunicating with each other through said chamber and leading therefrom to points adjacent to the normal water level line and the bottom oi the boiler, said valve being constructed and arranged to establish or interrupt conimunication between said discharge pipe and any of said draw oil pipes, and to interrupt circulation through said chamber when one of said draw ottl pipes and said discharge pipe are in communication.

In testimony whereof I aliix my signature.

GEORGE PURVIS. 

